I really like tinkeringtech's enclosure for PocketBeagle and made a couple revisions. There's a cutout for the CPU in the bot.
Aluminum case for BeagleBone Black on sale from Adafruit
keep those birdies safe
Unibody Aluminum Case for BeagleBone Black being sold by Adafruit
DIN Rail mounting enclosure for BeagleBone Black
Clear plastic BeagleBone Black enclosure available from Sparkfun.
BeagleBone Black Heatsink Enclosure
Enclosure for BeagleBone Black
A portable project case that you can put in your bag and take with you.